The invention relates to a tomographic apparatus for the production of transverse layer images of a radiography subject comprising an x-ray measuring arrangement with at least one x-ray source which is fed by an x-ray generator, which x-ray source generates an x-ray beam penetrating the radiography subject, the cross-sectional extent of said x-ray beam, perpendicular to the layer plane, being approximately equal to the layer thickness, and with a radiation receiver which determines the radiation intensity behind the subject, a rotating frame for rotating the x-ray source in the layer plane for the scanning of the radiography subject from different projections, and a measured value converter for the transformation of the signals delivered by the radiation receiver into a layer image, in which tomographic apparatus the high voltage transformer for the x-ray tube is operated with a medium frequency which is higher than the mains frequency and at least the component parts of the x-ray high voltage generator which are on the high voltage side are mounted on the rotating frame.
A tomographic apparatus of this type is described in the German OS No. 27 50 633 (U.S. Pat. No. 4,192,997 issued Mar. 11, 1980). In the case of this tomographic apparatus, a rapid movement of the x-ray source for scanning of a radiography subject is possible, because the high voltage-side components of the x-ray generator are mounted with the medium frequency generator on the rotating frame and are rotated together with the x-ray source during scanning of the radiography subject. Thus, no high voltage cables need be run to the x-ray source. The design of the x-ray high voltage supply to utilize a medium frequency generator results in the high voltage transformer being capable of being designed to be small and light-weight, so that for scanning of a radiography subject no large masses need be accelerated and braked. During the scanning of the radiography subject from different projections it is expedient to briefly switch on the x-ray tube for one projection in each instance, so that, in the case of 360 projections, for example, it is briefly switched on 360 times per scan cycle.